Recovering volatilized values including ethanol from warehouse atmospheres



Unite Ralph R. Kaiser, Cincinnati, Ohio, assignor to National Distillers and Chemical Corporation, New York, N. Y., a corporation of Virginia No- Drawing. Application February 21, 1955. Serial No. 489,781

2 Claims. (Cl. 260-643) This invention relates to the recovery of volatilized values, including particularly ethyl alcohol, which. are normally lost from whiskey during the aging in wooden barrels.

Whiskey is customarily aged in oak barrels which are stored in warehouses for periods of four years or more and, during such aging periods, a very considerable loss of volatile material, chiefly ethyl alcohol, normally occurs by vaporization through the wood of the barrels. Such losses amount to an approximate average of about two proof gallons per year per barrel for the first 4 to 5 years of storage. Hence, as a standard whiskey barrel holds approximately 50 gallons, such losses average about 20 percent ofv the original contents per barrel. over a five-year period. Since the warehouses in which whiskey barrels are stored are normally well; ventilated, the very substantial volatilized. values are Iost. to the surrounding atmosphere.

It is an object of this invention. to recover volatilized alcohol by efiicient and economical means...

It is a further object of this invention to. recover substantially all of the. volatilized values, including ethyl alcohol normally lost from Whiskey during, aging in wooden barrels, in such a manner as to permit further use of the recovered ethyl alcohol with a minimum of subsequent treatment.

These objects, and others which will hereinafter become evident, are accomplished according to this invention by passing the atmosphere surrounding the barrels and containing a suitable proportion of alcohol vapors into contact with an adsorption agent, a suitable illustrative example. of which is activated carbon, as well as. silica gel and other adsorbents for alcohol vapors. The vapors which are thus removed from the enriched air by the adsorption agent are subsequently recovered substantially completely by practice of this. invention. These steps. must be carried out under controlled conditions, and the entire operation performed in an integrated manner, in order to achieve the highly efficient recovery of volatilized values made possible by practice of the invention as is discussed more fully hereinafter.

The recovery of alcohol by the processof this invention is highly practical and economical when the degree Patent 0 of ventilation within the warehouse is suitably controlled 'i and certain other critical factors are regulated. Of such factors, the rate and control of the air removal from the warehouse have been found to be criticalfor the eltective recovery of alcohol.

tory constant alcoholic concentration in the atmosphere fonits. effective-recovery by the process of" this invention; whereas at a lower rate of air withdrawal (e. g., 252

For example, it has beeirxfoundr that, with a warehouse section having a; total volume of 443,500 cubic feet and a free volume of 317,500. cubic; feet and containing 15,000 barrels, the'removal of the. contained atmosphere at rates of 370 and' 760 S. F. (standard cubic feet per minute) resulted in a satisfacr C." F; M.)', alcohol recovery. was reduced tm'% ofthat 2,847,480 Patented Aug. 12, 1958 ICC Thus, in order to recover the alcohol from the atmosphe're in an economical manner, the. air must beremoved at. a sufiiciently high rate. to prevent substantial amounts of. the alcohol: from: diffusing through the walls. and minor openingsof the building. Preferably, however, the rate of air removal should not: be of such high magnitude that the cost of the power required to operate the fan, pump, or other air removal equipment, will render the process uneconomical;

In order that the vapors from which the volatilized values are to be recovered may not be unduly diluted with air, all sizable openings into the-warehouse should be closed. It is not necessary, however, that the Walls be made air tight although this may be desirable, in which case a controlled air inlet duct should be employed. Good results have been achieved in warehouses in which doors, windows, ventilators, fl'oor drains and other sizable openings have' been tightly closed. Undersuch conditions, sufiicient air normally enters the Warehouse through fine openings and. permits efiective operation of the process of this invention.

Under such closed warehouse conditions, and with controlled Withdrawal of the atmosphere therefrom, the alcoholic content of the atmosphere will remain at a substantially constantlevel and particularly suitable results are obtained by practice. of this invention when the alcoholic content of the atmosphere is maintained within the range of about 0.3.4 toaboutv 0.70- lb. per M. S. C. F. (thousand standard cubic feet). Since the rate of evaporation. of alcohol from the barrelvaries with the temperature, it may be expected that the alcoholic content will vary somewhat from the above range over anannual period. As an illustrative but not limitative example of operating conditions suitable. for practice of the invention, an. exhaust rate of 1.16 S. C. F. M. to. 2.39 S. C. F. M. per thousand cubic feet ofv free volume. in a filled warehouse. generally produces satisfactory results.

Thus, certain features of the invention are as follows:

(I) Openings in, the; warehouse. should be restricted to the extent that there will. be an. inward movement of air through the pores of the. warehouse walls when air is removed. at an economical, rate, such as by a. fan or an air pump, from the warehouse- ('2) The ,alcoholrcontaining air should be removed from. the warehouse to the recovery apparatus at a rate suchthat a high concentration. of alcohol is retained in the warehouse atmosphere and, at the, same time, the enriched warehouse atmosphere should not be permitted to. diifuse to the outside. atmosphere through. the walls and uncontrolled openings of. the. building.

The aforesaid features. are best utilized by. carrying out. the following steps Wh-ichconstitute actual operations: V i

(l) The warehouse should be sufficiently sealed in order to bring the alcohol'in'the air to a concentration at which it can be efiiciently removed. This is best accomplished closing all sizable openings. and, ridesired, can also include careful; caulking, sealing ofcracks,

, coatingor sprayingqmasonry and other structural matedesired minimum concentration ofialcohol is maintained while simultaneously maintaining: sufiicient exit. flow-to preventa substantial, if any, amount of. alcohol-leaving the building through unsealed cracks, porous wallaceilingsand floors.

(3.). The alcohol and. any other volatiles in: the withdrawn. air are trapped, preferablyby passage ofthe air stream overxan ad'sorbent such as activated carbon,-by adsorption of the volatiles thereon.

(4) The alcohol so trapped is subsequently recovered by an appropriate method.

(5) If desired, the recovered alcohol is concentrated and refined by distillation, chemical treatment, and/or exhaust rate of 760 S. C. F. M., the recovery was equivalent to 114 proof gallons per day, for the warehouse space involved.

The condensate containing the desorbed alcohol was such other methods as may be desired. 5 approximately 50 proof. An analysis of the condensate, The following example illustrates one method of succalculated to a strength of 50 proof gave the following cessfully carrying out the process of the invention, alresults: though it is in no way intended to limit the invention G./100l1tZrs specifically thereto. Acids (as acetic) .3 EXAMPLE Esters (as ethyl acetate) 42 This test utilized one floor of a plant size whiskey gfi (as acetaldehyde) n storage warehouse having a total volumeof 443,500 cubic f f "if feet and containing 15,000 barrels of aging whiskey hav- A por t1on of the condensate was fractlonally d1st1lled, ing a calculated volume of 126,000 cubic feet. All major eliminating a 10% heads cut and a 5% tails cut. The openings in the warehouse were closed, floor drains and middle run analyzed as follows: ventilators were sealed, and doors and windows were 1 k d d h Proof 92.1 Gaul, e an weat erstnpped' Acids (as acetic acid) g./ 100 liters" 1.8 Air was exhausted from the warehouse through a 5 Esters (as ethyl acetate) 26 inch duct by means of a 500 cubic feet per mlnute Aldehydes (as acetaldehyde) ugjloa liters" Q7 gl andhfour g i flfans fi g if keep As is apparent from the foregoing practice of the in e atmosp ere wit 1n t e oor we -m1xe e rate f i withdrawal was measured by a pilot tube vention in the controlled manner aforedescribed provides nected to a spiral manOmete1- Most f the was for effective recovery of alcohol which, in condensate exhausted to the atmosphere but a measured amount of form, is of q y that it is useful f Py 0f the the exhaustfrom the blower was passed through the ad- P P F for Whlch ethanol 15 F p y lncludlflg usage ower was use an t e rate 0 owt roug t e car on d was maintained at about 1 43 bi f t per minute the extent that all, or substantially all, of the alcohol b means f a fl meter d a b li For available for adsorption is recovered and, by actual tests, exhaust rates f 7 0 S C Fr M a larger blower and the alcohol recovered in condensate form as aforedean 8 i h duct were i i d scribed possessed suitable odor and taste characteristics. Pelleted Columbia activated carbon for the adsorption f t f ig dlsclosedfbflt a.11m1te d 3 was contained in a removable cylinder, 2 inches in diem 0 men s 0 6 Process 0 e mvemlon erem ametelby about 30 inches in length, surrounded by a presented, it is possible to produce still other embodiments steam jacket for use during the steaming cycles. Vapor depaftllflg the lnvelltlve concept hel'elll laden air entered the top of the column, passed through and 15 deslred therefore that only Such the carbon bed and was vented to the atmosphere. Durllmltatlons P imposed on the pp 61311115 35 ing the desorption cycle, steam was passed downward 63g i d thro h the 'acket urrou d' the c 1i (1 th d at is alme 1S1 throiigh the carbor i bedfaiiii then io a cond e iis iri A 40 1. A process for recovering volatilized values including valve on the condenser maintained a back pressure of ethyl alcohol normally lost from warehouses during the 15 p. s. i. g. on the column and gave, with a 20 minute aging of whiskey which comprises the steps in combinasteaming cycle, a condensate having a water-alcohol ratio tion of controlling the ethyl alcohol content of the atof approximately 3 to 1 by volume. mosphere within the warehouse to not less than a mini- The adsorption and desorption cycles were maintained mum concentration level of about 0.34 lb. per M. S. C. F. at approximately 160 and 20 minutes, respectively. of ethyl alcohol and maintaining said concentration level The alcoholic content of the attnosphere was deter- Within the range of about 0.34 to 0.70 lb. per M. S. C. F., mined by absorption of the alcohol from a known volume exhausting the alcohol-enriched atmosphere from the of air by means of anhydrous magnesium perchlorate warehouse at a rate of from 1.16 to 2.39 S. C. F. M. per with subsequent recovery by distillation and analysis by M. S. C. F. of free warehouse volume and controlling said oxidation with potassium dlchromate and sulfuric acid exhaust at a rate not greater than about 2.39 S. C. F. M. solution. A mine safety appliance combustible gas indiper M. S. C. F. of free Warehouse volume such as to catolr, prietiouslly calibrated vtl ith etlfiyl alcohol, was also maintain at least said -minimum concentration level of use an oun to ive resu ts wit 'n 3 f tho beth l alcoh l withi 'd a ho i tained by the perchlirate method. 0 Se 0 hau sted atm bsphere bv e i' an ad s orb eii t vfh sr e y th e vo lii- The data obtained in this test are shown in Table I. tile values including ethyl alcohol are adsorbed thereon Table I Condensate from Carbon Alcoholin Rate Air Alcohol Steaming the Percent Exhaust Rate, Adsorber No. of Atmosover Available Adsorber Alcohol S. C. F. M. Cycle, Cycles phere, Carbon for Ad- Re- Minutes Average, Adsorber, sorptlon, covered gm./cu. it. C. F. M. gm. cc. a1gnil. 1

165 7 0. 240 1. 43 396 1, 785 412 104 160 8 0. 240 1. 43 45s 2, 305 392 7 0. 230 1. 4.3 368 2, 060 320 87 12a 8323 1a 4a as e: a 160 8 0I 247 11 43 475 21 300 465 as 240 1 0.163 1. 51 59. 5 468 61 102 313 1 0. 149 1. 43 66. 7 330 61 91 The average recovery of alcohol was 93.5%. At the exhaust rate of 370 S. C. F. M., the recovery of alcohol.

was equivalent to 98 proof gallons per day; and at the 75 and thereafter recovering said volatile values including ethyl alcohol therefrom.

2. A process for recovering ethyl alcohol normally lost from warehouses during the aging of whiskey which comprises the steps in combination of controlling the ethyl alcohol content of the atmosphere within the warehouse to not less than a minimum concentration level of about 0.34 lb. per M. S. C. F. of ethyl alcohol and maintaining said concentration level within the range of about 0.34 to 0.70 lb. per M. S. C. F., exhausting the alcohol-containing atmosphere from the Warehouse at a rate of from 1.16 to 2.39 S. C. F. M. per M. S. C. F. of free warehouse volume and controlling said exhaust at a rate not greater than about 2.39 S. C. F. M. per M. S. C. F. of free Warehouse volume such as to maintain at least said minimum concentration level of ethyl alcohol within said warehouse,

passing said exhausted atmosphere over an activated carbon adsorbent whereby the ethyl alcohol is adsorbed thereon, and thereafter desorbing and recovering said ethyl a1- cohol therefrom.

Mantell: Adsorption (2nd edit, 1951), McGraw-Hill, New York, page 254, pages 231-7, 239, and chapter 12. 

1. A PROCESS FOR RECOVERING VOLATILIZED VALUES INCLUDING ETHYL ALCOHOL NORMALLY LOST FROM WAREHOUSES DURING THE AGING OF WHISKEY WHICH COMPRISES THE STEPS IN COMBINATION OF CONTROLLING THE ETHYL ALCOHOL CONTENT OF THE ATMOSPHERE WITHIN THE WAREHOUSE TO NOT LESS THAN A MINIMUM CONCENTRATION LEVEL OF ABOUT 0.34 LB. PER M.S.C.F. OF ETHYL ALCOHOL AND MAINTAINING SAID CONCENTRATION LEVEL WITHIN THE RANGE OF ABOUT 0.34 TO 0.70 LB. PER M.S.C.F. EXHAUSTING THE ALCOHOL-ENRICHED ATMOSPHERE FROM THE WAREHOUSE AT A RATE OF FROM 1.16 TO 2.39 S.C.F.M. PER M.S.C.F. OF FREE WAREHOUSE VOLUME AND CONTROLLING SAID EXHAUST AT A RATE NOT GREATER THAN ABOUT 2.39 S.C.F.M. PER M.S.C.F. OF FREE WAREHOUSE VOLUME SUCH AS TO MAINTAIN AT LEAST SAID MINIMUM CONCENTRATION LEVEL OF ETHYL ALCOHOL WITHIN SAID WAREHOUSE, PASSING SAID EXHAUSTED ATMOSPHERE OVER AN ADSORBENT WHEREBY THE VOLATILE VALUES INCLUDING ETHYL ALCOHOL ARE ADSORBED THEREON AND THEREAFTER RECOVERING SAID VOLATILE VALUES INCLUDING ETHYUL ALCOHOL THEREFROM. 